1. Field of the Invention
The invention relates to invalid hoists for use with lifting slings in which invalids are suspended during lifting. It is particularly concerned with such a hoist which embodies a sling hanger presenting spaced sling attachment points and mounted at the outer end of a lifting arm of the hoist so as to pivot about a rigid vertical bearing axis.
The term "rigid" as used herein with reference to said vertical bearing has the special meaning that the bearing axis remains substantially vertical throughout the range of lifting movement of the arm. The rigid vertical bearing prevents the free pendulum-like swinging movement of a suspended invalid which is a marked disadvantage of a hoist having a freely suspended sling hanger without such a bearing. Thus the rigid vertical bearing provides a considerable advantage during transport of a suspended invalid with a mobile hoist as it prevents possible injury and provides a psychologically important feeling of security.
2. Description of the Prior Art
Prior hoists employing such a bearing have the disadvantage that the sling hanger adopts a fixed disposition relative to the bearing axis which limits its range of application so far as different lifting procedures are concerned. This disadvantage does not arise with a simple hanger which presents only two spaced suspension points but it is immediately apparent with a more complex hanger arrangement presenting more than two suspension points, for example two spaced pairs of suspension points to which separate back and seat/leg slings, or an equivalent one-piece sling, can be attached. In this case the arrangement is not readily adaptable for the support of an invalid in alternative dispositions.